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https://git.FreeBSD.org/src.git
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3e65b9c6e6
Add an API for alerting internal libc routines to the presence of "unsafe" paths post-chroot, and use it in ftpd. [11:07] Fix a buffer overflow in telnetd. [11:08] Make pam_ssh ignore unpassphrased keys unless the "nullok" option is specified. [11:09] Add sanity checking of service names in pam_start. [11:10] Approved by: so (cperciva) Approved by: re (bz) Security: FreeBSD-SA-11:06.bind Security: FreeBSD-SA-11:07.chroot Security: FreeBSD-SA-11:08.telnetd Security: FreeBSD-SA-11:09.pam_ssh Security: FreeBSD-SA-11:10.pam
206 lines
5.6 KiB
C
206 lines
5.6 KiB
C
/*
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* Copyright (c) 1988, 1993, 1994
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software written by Ken Arnold and
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* published in UNIX Review, Vol. 6, No. 8.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef lint
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#if 0
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static char sccsid[] = "@(#)popen.c 8.3 (Berkeley) 4/6/94";
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#endif
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#endif /* not lint */
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <netinet/in.h>
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#include <errno.h>
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#include <glob.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include "extern.h"
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#include "pathnames.h"
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#include <syslog.h>
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#include <time.h>
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#define MAXUSRARGS 100
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#define MAXGLOBARGS 1000
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/*
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* Special version of popen which avoids call to shell. This ensures noone
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* may create a pipe to a hidden program as a side effect of a list or dir
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* command.
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*/
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static int *pids;
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static int fds;
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FILE *
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ftpd_popen(char *program, char *type)
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{
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char *cp;
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FILE *iop;
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int argc, gargc, pdes[2], pid;
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char **pop, *argv[MAXUSRARGS], *gargv[MAXGLOBARGS];
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if (((*type != 'r') && (*type != 'w')) || type[1])
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return (NULL);
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if (!pids) {
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if ((fds = getdtablesize()) <= 0)
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return (NULL);
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if ((pids = malloc(fds * sizeof(int))) == NULL)
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return (NULL);
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memset(pids, 0, fds * sizeof(int));
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}
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if (pipe(pdes) < 0)
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return (NULL);
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/* break up string into pieces */
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for (argc = 0, cp = program; argc < MAXUSRARGS; cp = NULL) {
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if (!(argv[argc++] = strtok(cp, " \t\n")))
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break;
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}
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argv[argc - 1] = NULL;
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/* glob each piece */
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gargv[0] = argv[0];
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for (gargc = argc = 1; argv[argc] && gargc < (MAXGLOBARGS-1); argc++) {
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glob_t gl;
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int flags = GLOB_BRACE|GLOB_NOCHECK|GLOB_TILDE;
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memset(&gl, 0, sizeof(gl));
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gl.gl_matchc = MAXGLOBARGS;
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flags |= GLOB_LIMIT;
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if (glob(argv[argc], flags, NULL, &gl))
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gargv[gargc++] = strdup(argv[argc]);
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else if (gl.gl_pathc > 0) {
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for (pop = gl.gl_pathv; *pop && gargc < (MAXGLOBARGS-1);
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pop++)
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gargv[gargc++] = strdup(*pop);
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}
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globfree(&gl);
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}
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gargv[gargc] = NULL;
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iop = NULL;
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fflush(NULL);
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pid = (strcmp(gargv[0], _PATH_LS) == 0) ? fork() : vfork();
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switch(pid) {
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case -1: /* error */
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(void)close(pdes[0]);
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(void)close(pdes[1]);
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goto pfree;
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/* NOTREACHED */
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case 0: /* child */
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if (*type == 'r') {
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if (pdes[1] != STDOUT_FILENO) {
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dup2(pdes[1], STDOUT_FILENO);
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(void)close(pdes[1]);
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}
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dup2(STDOUT_FILENO, STDERR_FILENO); /* stderr too! */
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(void)close(pdes[0]);
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} else {
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if (pdes[0] != STDIN_FILENO) {
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dup2(pdes[0], STDIN_FILENO);
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(void)close(pdes[0]);
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}
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(void)close(pdes[1]);
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}
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/* Drop privileges before proceeding */
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if (getuid() != geteuid() && setuid(geteuid()) < 0)
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_exit(1);
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if (strcmp(gargv[0], _PATH_LS) == 0) {
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/* Reset getopt for ls_main() */
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optreset = optind = optopt = 1;
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/* Close syslogging to remove pwd.db missing msgs */
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closelog();
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/* Trigger to sense new /etc/localtime after chroot */
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if (getenv("TZ") == NULL) {
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setenv("TZ", "", 0);
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tzset();
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unsetenv("TZ");
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tzset();
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}
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exit(ls_main(gargc, gargv));
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}
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execv(gargv[0], gargv);
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_exit(1);
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}
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/* parent; assume fdopen can't fail... */
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if (*type == 'r') {
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iop = fdopen(pdes[0], type);
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(void)close(pdes[1]);
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} else {
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iop = fdopen(pdes[1], type);
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(void)close(pdes[0]);
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}
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pids[fileno(iop)] = pid;
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pfree: for (argc = 1; gargv[argc] != NULL; argc++)
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free(gargv[argc]);
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return (iop);
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}
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int
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ftpd_pclose(FILE *iop)
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{
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int fdes, omask, status;
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pid_t pid;
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/*
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* pclose returns -1 if stream is not associated with a
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* `popened' command, or, if already `pclosed'.
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*/
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if (pids == 0 || pids[fdes = fileno(iop)] == 0)
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return (-1);
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(void)fclose(iop);
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omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGHUP));
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while ((pid = waitpid(pids[fdes], &status, 0)) < 0 && errno == EINTR)
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continue;
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(void)sigsetmask(omask);
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pids[fdes] = 0;
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if (pid < 0)
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return (pid);
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if (WIFEXITED(status))
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return (WEXITSTATUS(status));
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return (1);
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}
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